Hydraulic and resilient cushioned railway car draft appliance

ABSTRACT

A combined hydraulic and resiliently cushioned railway car draft appliance employing a fluid cylinder, a piston disposed within the cylinder, a piston rod attached to the piston and connected to be moved by buff or draft forces applied to the draft appliance, and having a urethane collar disposed within the cylinder surrounding the piston rod. The urethane collar is effective to improve train action by providing a variable cushioned resistance in draft and does not bottom out as a spring might to allow metal to metal contact. The hydraulic section and coupling yoke section are separably connected thereby facilitating installation and removal. No flow control, or pressure relief valves or bellows are employed to accomplish the fluid cushioning thereby eliminating many potential repair problems.

States ate @lrierici et a1.

[54] HYDRAULIC AND RESHJENT CUSHIONED RAILWAY CAR DRAFT APPLKANCE [75] Inventors: Osvaldo Frank Chierici, Elmhurst;

James Thomas Smith, Wilmette, both of 111.

[73] Assignee: Holland Company, Lombard, 111.

[22] Filed: Sept. 14, 1970 [21] Appl. No.: 71,858

[52] US. Cl ..213/8 [51] Int. Cl ..B6lg 9/12 [58] Field of Search.2l3/8, 43, 223; 267/64 R, 64 A,

[56] References Cited UNITED STATES PATENTS 3,301,410 1/1967 Seay ..2l3/43 3,194,355 7/1965 Jeromson,.lr..... ....188/315 3,341,189 9/1967 Rumsey ..2l3/43 3,152,699 10/1964 Vickerman.... ..213/43 3,559,818 2/1971 Knippel ..2l3/43 3,047,162 7/1962 Blake ..2l3/43 3,176,856 4/1965 Smith ..2l3/43 ]Mlarcl1 20, 1973 3,334,757 8/1967 Peterson ..213/43 3,378,149 4/1968 Powell ..213/43 3,515,286 6/1970 Powell ..213/43 3,568,855 3/1971 Seay ..213/43 Primary Examiner-Drayton E. Hoffman Attorney-F rank R. Thienpont [5 7 ABSTRACT A combined hydraulic and resiliently cushioned railway car draft appliance employing a fluid cylinder, a piston disposed within the cylinder, a piston rod attached to the piston and connected to be moved by buff or draft forces applied to the draft appliance, and having a urethane collar disposed within the cylinder surrounding the piston rod. The urethane collar is effective to improve train action by providing a variable cushioned resistance in draft and does not bottom out as a spring might to allow metal to metal contact. The hydraulic section and coupling yoke section are separably connected thereby facilitating installation and removal. No flow control, or pressure relief valves or bellows are employed to accomplish the fluid problems.

1 Claim, 12 Drawing Figures HYDRAULIC AND RESILIENT CUSHIONED RAILWAY CAR DRAFT APPLIANCE BACKGROUND OF THE INVENTION This invention relates to railway draft appliances and more particularly to appliances of the type employing springs and hydraulic cushioning.

Hydraulically buffered or cushioned coupling devices have become commonplace on modern railway rolling stock. Such devices have become almost essential as railway cars have increased in size and weight in order to protect the cargo carried by the cars as well as the cars themselves from damage due to the shocks and jolts encountered in coupling cars together and in taking up the normal slack in starting and stopping a train.

In the design of existing hydraulic devices, most are concerned primarily with cushioning shocks due to buff forces. That is the type of force encountered when two cars are coupled together. One car normally is rolling at a low but significant velocity when it is coupled to a stationary car. The momentum of the moving car is brought abruptly to zero by the impact with the sta tionary car.

The hydraulic buffering devices absorb the impact by causing a piston to compress and displace a fluid. The pressures generated during such impact may approach dangerously high levels so pressure relief valves normally are provided, or some other means of pressure accumulation is provided.

Substantial shock due to draft forces also is encountered frequently. There is a certain amount of slack in each set of couplings, and in the last or near to last car of a long train, the jolt in starting this car is substantial. The hydraulic coupling devices currently in use generally are not very effective in cushioning such forces in draft.

SUMMARY OF THE INVENTION The combined resilient and hydraulic cushioning draft appliance of the present invention provides an improved fluid displacement cylinder effective to cushion buff forces without the use of flow control or pressure relief valves. The cylinder is adapted to be mounted within the center sill of a railway car and is connected to be actuated by a coupler mounted so as to be movable longitudinally within the center sill. The hydraulic cylinder is capable of being installed or removed from within the center sill without removing the coupler.

The hydraulic cylinder is particularly effective to cushion forces in draft by the provision of a compressible urethane collar surrounding the piston rod within the cylinder. The urethane collar does not bottom-out as a coil spring might so as to permit direct metal to metal contact within the cylinder.

The present invention also includes an improved centering spring mechanism effective to restore the hydraulic cylinder to its operative position prior to the next impact. The spring mechanism includes a coiled compression spring assembly with a lost motion connection at each end of its length whereby the spring is compressed for either direction of travel of the coupling yoke when buff or draft forces are applied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is plan view, partially in phantom, of the hydraulic and resilient cushioned railway car draft appliance of the present invention;

FIG. 2 is a longitudinal view in elevation, partially in section, of the draft appliance taken on line 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view of the hydraulic portion of the draft appliance of FIG. 2;

FIG. 4 is a top view of a portion of the draft appliance as coupled to another appliance of the same basic design;

FIG. 5 is a sectional end view of the draft appliance looking forwardly as taken on line 5-5 of FIG. 1;

FIG. 6 is a sectional view through a portion of the hydraulic cushion mechanism looking rearwardly as taken on line 6-6 of FIG. 1;

FIG. 7 is a sectional view looking rearwardly and taken on line 7-7 of FIG. 1;

FIG. 8 is a sectional view through the piston rod and coupler housing looking forwardly as taken on line 8- 8 of FIG. 1;

FIG. 9 is a sectional view through the coupler shank and coupler housing looking rearwardly as taken on line 9-9 of FIG. 1;

FIG. 10 is an enlarged view in elevation, partially in section, of the resilient cushion mechanism for the appliance;

FIG. 11 is an end view, partially in phantom, of the striker plate taken on line 11-1 1 of FIG. 10; and

' FIG. 12 is an end view looking forwardly as taken on line 12-12 of FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENT The, draft appliance of the present invention is designated generally by the numeral 20 and includes an hydraulic cushion section 22 and a resilient coupling section 24 both of which are interconnected and operably mounted within one end of a center sill 26 of a railroad car. I

The center sill 26 is well known in modern railway cars and comprises an inverted U-shaped steel channel member, substantially square in cross section, and having outwardly extending flanges 27 and 28 adjacent its open bottom.

The hydraulic cushion section 22 comprises a cylindrical shell 30 formed with an internal cylindrical bore 31, a double acting piston 32 slideably disposed within the bore 31, a piston rod 33 attached to the piston 32, a longitudinally extending urethane collar 34 surrounding the piston rod 33, and an hydraulic fluid reservoir 35. The cylindrical shell 30 is closed at its left end by an end wall 36 which abuts against a cylinder stop 39. The stop 39 is bolted to the flanges 27 and 28 of the center sill 26 as seen in FIG. 6 and includes vertically extending stop members 39A, 39B and 39C against which the end wall 38 abuts. A cylindrical sleeve 38A surrounds the piston rod 33 and is fixed in the end wall 38 by suitable means such as by welding. The cylindrical sleeve carries piston rod bearing bushing means. The cylinder 30 is supported withinthe sill 26 by cylinder carrier plates 40 and 41 which are also bolted to the flanges 27 and 28 of the center sill 26.

Referring particularly to FIG. 3 and FIG. 5, the hydraulic fluid reservoir 35 which is generally in the form of an enclosed V-shaped cavity, is mounted on top of the cylinder 30. The reservoir 35 also has an integral extension 45 at its right end which extends beyond the right end of the cylinder 30. A port 46 extending through sleeve 38 a communicates with groove 460 formed in the inner surface of bushing 47. The port 46 is effective to act as a high-pressure release port directing high pressure oil seepage from along the piston rod back into the reservoir 35. A plurality of radial ports 50, 51, 52, 53, 54, and 55 are logarithmically spaced along the length of the shell 30 and permit the displacement of hydraulic fluid from the bore 31 into the fluid reservoir 35 during movement of the piston 32 to the left as indicated in FIG. 3. An additional radial port 56 permits displacement of hydraulic fluid from the reservoir 35 into and out of the cavity 31A behind the piston 32 during the application of buff and draft forces respectively. A fill plug 57 is provided in the top of the reservoir 35 for filling the reservoir 35 with fluid 58. A locating pad 59 is welded within the center sill 26, and the upper surface of the reservoir 35 abuts against it for proper positioning of the cylinder 30 within the sill 26.

The embodiment of the hydraulic cushion section 22 shown and described is a particularly advantageous construction because it contains no flow control or pressure relief valves of any sort or rubber bellows thereby eliminating many of the potential problems normally created by such devices.

The piston 32 carries a cast iron piston ring 42 within an annular groove 43 formed in the piston 32. This ring 42 has direct contact with the internal surface of the cylinder and prevents galling due to contact of steel against steel in the event of slight misalignment of the piston 32 within the bore 31.

A particularly advantageous feature of this invention is the urethane collar 34 surrounding the piston rod 33 within the cavity 31A which acts as a resilient cushion member when draft forces are applied to the piston rod 33. The urethane collar 34 is compressible in draft, but unlike a coil spring, does not bottom out to allow a metal against metal contact. This results in improved train performance. Also, the urethane material of which the collar 34 is made is impervious to oil and, therefore, does not deteriorate in the presence of the hydraulic fluid 58. The urethane collar does not abrade the piston rod 33 as a spring might. The collar is porous to the fluid Y58, and returns to its original shape following compression.

In operation, the function of the hydraulic cushion mechanism 22 is as follows:

When a sudden buff or compression force is applied to the piston rod 33, the piston 32 is forced to the left, as shown in FIG. 3, slightly compressing the fluid 58 within the bore 31. The pressure applied to the fluid 58 forces the fluid out through the ports 50-55 and into the reservoir 35. Initially, whileall of the ports 50-55 are open, the fluid 58 within the cavity 31 is permitted to escape relatively quickly. As the piston 32 moves to the left, the ports 50, 51, and 52 are successively cut off reducing the number of escape paths for the fluid 58. Still further movement of the piston 32 to the left cuts off additional ports 53 and 54 and causes an exponential build up of pressure within the bore 31. The cushioning effect of the mechanism 22, therefore, increases with increased linear travel of the piston 32 due to the application of buff forces.

A portion of the fluid 58 expelled from the bore 31 into the reservoir 35 then passes through the port 56 into the cavity formed by the bore 31A behind the piston 32. Fluid 58 also enters the bore 31A through ports 50, 51, etc., as the piston 32 moves to the left to open them. The presence of this fluid has the effect of limiting rebound of the piston 32 following the sudden application of a buff force to the piston rod 33. The piston 32 must be returned to a neutral position following the application of either buff or draft forces to the mechanism 22. This return function is performed byv the resilient coupling section 24 as will be described hereinafter.

The application of a draft force to the piston rod 33 tends to move the piston 32 to the right, as shown in FIG. 3, compressing the fluid 58 and the urethane collar 34 present within the cavity 31A. The urethane collar 34 reduces the effective volume of the fluid 58 within the bore 31A and the fluid 58 is expelled into the reservoir 35 through the port 56. The compressed collar 34 may partially block the port 56 to restrict oil flow therethrough. Further compression of the collar 34 requires that the fluid 58 be squeezed out of the collar 34 to escape from the cavity 31A. The collar 34 therefore has the effect of providing a variably increasing resistance to the draft forces applied to the piston rod 33.

Referring now to FIGS. 1 and 2, and to FIGS. 5-9, the resilient coupling section 24 is seen to comprise a yoke or housing carrying a standard car coupler 71, and return spring mechanisms 72 and 73. The yoke 70 is an elongated welded steel structure, of a generally inverted U-shape construction and square in cross-section, mounted to slide within the center sill 26. The yoke 70 may include a horizontally extending top plate 70A, vertically extending side walls 70B and 70C and bottom inwardly extending flanges 70D and 7012 connected to side walls 70B-and 70C respectively. The yoke 70 carries a striker plate 75 formed with a rectangular aperture 76 through which the shank 77 of the coupler 71 extends. The shank 77 is formed with a transverse slot 78 through which a draft key 79 extends and is secured to the walls of the yoke 70. The yoke 70 is supported within the center sill 26 by a yoke carrier 80 bolted to the flanges 27 and 28. A wear plate 81 is welded to the underside of the yoke 70, i.e., to the flanges 70D and 70E and rides on top of a wear plate 82 attached to the yoke carrier 80. Another wear plate 83 is mounted within the aperture 76 of the striker plate 75 for supporting the shank 77 of the coupler 71.

Vertical transversely extending retaining plates 85 and 86 are welded to the interior of the yoke 70. A plurality of transversely extending reinforcing members 87, 88, 89, and 90 are also welded to the interior of the yoke 70. The member 90 also serves as a spacer between the retaining plates 85 and 86. The retaining plate 86 is formed with a slot 91 through which the piston rod 33 extends.

A piston rod cap 93 and stop lug 94 are trapped between the retaining plates 85 and 86. The cap 93 is threaded to one end of the piston rod 33 and is rigidly attached to the stop lug 94. The lug 94 extends downwardly through a central longitudinally extending opening 95 formed in the yoke 70 by the flanges 70D and 70E and rides on a. rod cap carrier plate 96 mounted by bolts between the cylinder stop 39 and the yoke carrier 80. The side walls of yoke 70 are cut back on a slant at 97 so that it does not strike the cylinder stop 39 during buff travel. The stop lug 94 is designed so that its downwardly extending portion will function as an over-solid stop being adapted to abut against piston stop 94A in buff and 80A in draft.

An important feature of the present design is that the hydraulic cushion section 22 is removable without disturbing the resilient coupling section 24. This is accomplished by first unbolting the rod cap carrier plate 96, then unbolting the cylinder stop 39, and finally unbolting the cylinder carrier plates 40 and 41. The

cylinder 30, piston rod 33, and reservoir 35 are then removable as a unit. The section 22 is reinstalled or replaced by following the above described steps in the reverse order. The fact that the resilient coupling section 24 is separable from the hydraulic cushion section 22 is also important from the standpoint of repair and replacement of one or the other sections in that either may be replaced while retaining the other in service.

Referring now to FIGS. 10, 11, and 12, the centering return spring mechanisms 72 and 73 of the section 24 will now be described. Only the mechanism 72 is described in detail, since the mechanism 73 is substantially identical to the mechanism 72. The spring mechanism 72 comprises a pair of coiled compression springs 100 and 101, a central large diameter buff spring rod 102, a pair of relatively smaller diameter, external draft spring rods 103 and 104, a spring stop base 105, a plurality of spring follower plates 106, 107, and 108, and a backup plate 109.

The spring stop base 105 comprises a vertically extending spring stop base plate 111 secured to the external vertical wall of the center sill 26 by suitable means such as by welding or bolting, a pair of horizontally extending spring stop stiffeners 112 and 113 secured to the plate 1 1 1 by suitable means such as by welding, and a pair of draft rod stop lugs 1 14 and 115 welded to the stiffeners 112 and 113, respectively. The draft spring rods 103 and 104 extend longitudinally through bores in the stop lugs 114 and 115, respectively, and are slideable therethrough.

The backup plate 109 is secured to the rear face of the striker plate 75 by welding or other suitable means and may have a threaded central bore 1 19 for receiving a threaded end 120 of the buff spring rod 102. The rod 102 extends loosely through central bores 121, 122, and 123 formed in the spring follower plates 106, 107, and 108, respectively. A square washer 124 is welded to the other end of the rod 102 and constitutes a buff spring stop. The diagonal dimension of this stop 124 is greater than the vertical distance between the stiffeners 112 and 113 so that the rod 102 cannot become unthreaded from the plate 109.

The spring mechanism 72 may be assembled initially by passing the buff spring rod 102 successively through the follower plate 106, spring 101, follower plate 107, spring 100, and follower plate 108. The length of the rod 102 and springs 100 and 101 are designed so that in the assembled relationship a desired preload is placed on the springs 100 and 101. The assembly may be compressed by a suitable rig (not shown) to the desired preload for the springs 100 and 101 before threading into the backup plate 109. For permanent installation, it may be noted that the rod 102 can be welded to the plate 109 before the plate 109 is welded to the striker plate 75.

The next step in the assembly of the mechanism 72 is to pass the draft spring rods 103 and 104 through the stop lugs 114 and 115, through the follower plates 106 and 107 and attach them to the follower plate 108. The plates 106 and 107 are formed with apertures 126 and 127 through which the rods 103 and 104 loosely extend. The ends of the rods 103 and 104 may be threaded into apertures 128 formed in the plate 108 or may be permanently secured therein by welding. Draft rod stop nuts 133 and 134 are secured to the opposite ends of the rods 103 and 104.

In operation, the centering spring mechanism 72 functions as follows:

When a buff force is applied to the yoke 70, the striker plate 75 is caused to be moved to the left as shown in FIG. 10 compressing the springs 100 and 101 between the follower plates 106, 107 and 108 and against the stop base 105. The buff spring rod 102 is freely slidable through openings 121 and 122 of follower plates 106 and 107 respectively, and the rods 103 and 104 are freely slidable to the left through the stop lugs 114 and 115. After the impact of the buff force, the springs 100 and 101 force the striker plate 75 and rods 102, 103, and 104 back to the neutral position shown in FIG. 10. The mechanism 72 is then condi tioned for the next impact, either in draft or buff.

When a draft force is applied to the yoke 70, the striker plate 75 and back-up plate 109 are caused to be moved to the right as shown in FIG. 10 pulling the rod 102 and spring follower plate 106 with them. The rods 103 and 104 are held in place by the stop base 105 and the follower plate 108 is held with them. The springs 100 and 101 are thus compressed between the plates 106 and 108 until the draft force is removed. When this draft force is removed, the springs 100 and 101 again cause the striker plate 75 and rods 102, 103, and 104 to return to the neutral position shown in FIG. 10.

As described previously, it may be desirable to have the hydraulic cushion section 22 removable from the center sill independently of the resilient coupling section 24. The coupler 71 may be removed simply by removing the coupler key 79 and withdrawing the coupler shank 77 from the yoke 70.

The yoke may be removed by unbolting the carrier plate 96. The centering spring mechanisms 72 and 73 are disconnected by providing a suitable point of detachment. In the event the back-up plate 109 and striker plate are bolted together, this may be accomplished by unbolting the back-up plate 109 from the striker plate 75, in which case the spring mechanisms 72 and 73 are left attached to the center sill 26. Alternatively, if the base plate 1 l 1 is bolted to the center sill 26 (instead of being welded thereto), these elements may be unbolted in which case the mechanisms 72 and 73 are removed along with the yoke 70. Still a third possibility is to unthread the rods 103 and 104 from the follower plate 108, in which case the base 105 and rods 103 and 104 remain with the center sill 26, and the springs and 101 and rod 102 are removed along with the yoke 70. The final step in the removal of the yoke 70 is to unbolt the yoke carrier 80 from the flanges 27 and 28 of the center sill 26.

The forces in buff and draft acting on the draft appliance are applied by or through a corresponding appliance on another railway car, as shown in FIG. 4. The impact that occurs when the two couplers 71 and 71A are brought together produces buff forces in both appliances. Sudden forces applied to the couplings in starting a train, for example, produce draft forces in both appliances. The improved draft appliance 20 of the present invention is effective to cushion both types of forces so as to protect both the railway cars and the cargo they carry.

It will be apparent that this invention provides an improved draft appliance of a relatively simplified construction. It does not depend upon the use of check valves, pressure relief valves and rubber bellows to provide appropriate cushioning effects, those items often being subject to rapid deterioration. The invention also provides a very effective cushioning means for draft forces in the nature of a resilient urethane collar operatively associated with the piston rod and piston head. The urethane collar has the distinct advantage of being impervious to the hydraulic fluid used in the hydraulic device and does not score the piston rod. The draft appliance is advantageously constructed to permit easy installation and removal of certain portions thereof without handling the whole device.

The embodiment shown and described is by way of example only and it should be understood that many changes may be made thereto without departing from the spirit of the invention. The invention should not be construed as limited to the embodiment described except insofar as the claims may be so limited.

What is claimed is:

1. In a railway car draft appliance having a coupler carrying yoke slidably mounted within the center sill of the car a centering return spring mechanism for returning the coupler to a normal position comprising:

a mounting base adapted to be rigidly attached to the center sill;

a back-up plate rigidly attached to the longitudinally movable yoke;

a longitudinally extending central rod rigidly attached to said back-up plate;

coil spring means associated with said central rod and pre-loaded a predetermined amount under compression;

a first spring follower plate slidably mounted on said central rod and disposed between one end of said spring and said back-up plate;

a second spring follower plate also slidably mounted on said central rod and disposed between said mounting base and the other end of said spring means; and

a pair of longitudinally extending rods disposed parallel to said central rod and extending loosely through said mounting base and said second spring follower plate and rigidly attached to said first spring follower plate. 

1. In a railway car draft appliance having a coupler carrying yoke slidably mounted within the center sill of the car a centering return spring mechanism for returning the coupler to a normal position comprising: a mounting base adapted to be rigidly attached to the center sill; a back-up plate rigidly attached to the longitudinally movable yoke; a longitudinally extending central rod rigidly attached to said back-up plate; coil spring means associated with said central rod and preloaded a predetermined amount under compression; a first spring follower plate slidably mounted on said central rod and disposed between one end of said spring and said backup plate; a second spring follower plate also slidably mounted on said central rod and disposed between said mounting base and the other end of saId spring means; and a pair of longitudinally extending rods disposed parallel to said central rod and extending loosely through said mounting base and said second spring follower plate and rigidly attached to said first spring follower plate. 